Garbage tankage extraction



J 30, 1931. E. w. M CULLOUGH GARBAGE TANKAGE EXTRACT-ION Filed Oct 17 run INVENTOR.

ATTORNEY-S.

a Q 80 0 Q0 O o ooooo w Patented June 30, 1931 PATENT OFFICE ERVIN W. MCCULLQUGH, OF INDIANAPOLIS, INDIANA.

GARBAGE TANKAGE EXTRACTION Application filed October 17, 1925. Serial No. 63,163.

stituent or desired portions thereof. Such a solvent is gasoline or naphtha for the removal of grease and other solvents are employed for removing other constituents, such solvents being well known and having an affinity for the particular portion or constituent desired to be removed. The usual solvents having an afiinity for certain constituents are Well known to skilled chemists and are not set forth herein.

The chief feature of the invention consists in subjection of a processed garbage or tankage, having a peculiar character, to a process to abstract the desired constituent therefrom with the aid ofa solvent and without decan-' tation and such a processed garbage may be produced by followin the steps set forth in my prior application erial.N0.'698,106 filed March 10, 1924, or briefly 'as follows: The green garbage is taken from the pit mechanically and is conveyed to the reduction tanks in the reduction building. In these tanks the whole cycle of operations is performedwithout removing or handling the charge until it is completely cooked and dried. This is an important feature of sanitary garbage reduc-' tion. By eliminating the direct heat drier the necessity of piling the hot, wet garbage is obviated and all danger of scorching and burning the tankage is eliminated. In brief, it converts the cooking and drying operations into a compact, sanitary operation quickly performed in the same tank. Each tank has percolatable in the mass thereby preventingcomplete permeation by a suitable solvent when it is employed to remove a desired con-,

.while it is being dried. As a rule, the drying under vacuum proceeds for a period of about discharged into conveyors and carried to the a capacity of three and one-half tons ofgreen garbage under normal working conditions, and is capable ofturning out two charges in twenty-four hours with every particle of the charge thoroughly cooked. Livesteam, at about eighty pounds pressure, is admitted into direct contact with the raw garbage for a period of" about three hours. Meanwhile the tank is vented and the pressure built up to eighty pounds within the tank. After cooking the charge is allowed to settle and the free water from the cooking process is decanted as far as. possible, after which the charge may be steam pressed further to expel the free water. a I Y After pressing, the charge is dried, usually under fifteen 'or more inches. of vacuum, by-

jmeansjof a jacket into which steam is admitted. The charge is stirred or agitated four hours. I

When the tankage is dry it is automatically preparation'house. Here it may be degreased by the conventional degrea'sing methods, or it may be .processed. mechanically to remove from it material such as pins, phonograph needles, tacks, glass, crockery, bits of wood and the like. Coffee grounds, paper, eggshells-and similar rubbish are also removed. The removal of deleterious substances is controlled by chemical checks. The result isan animal food of encouraging prospective value.

A further feature of the invention consists 'in the fact that the process hereafter set forth is not only adapted to handle the product's derived fro-m a plant of the character described but is adapted to handle what is normally known as the Chamberlin processed garbage and theprocess is also adapted to handle the rejects of the Indianapolis plant for each of the rejected particles has clinging to it a coating of grease, as well as minute portions 5 of the-desired food value constituent. When the bulk of material rejected is sufficient, this material is placed in an extraction tank of a character hereinafter described and processed in the same way asthe tankage set forth is sired.

processed to obtain therefrom the desired constituent. The tankage obtained from the Indianapolis garbage plant is relatively fine or greatly disintegrated and when subjected to the usual degreasing cycle heretofore employed this tankage packs and cannot be penetrated to any considerable extent in any rcasonable length of time by the usual solvent even if the tank be agitated and the solvent be under pressure. Furthermore, when the 'last mentioned operations are utilized the finer particles of tankage are carried off by the solvent when it is removed.

The present invention operates in spite of the fact that the tankage is normally nonpercolatable as set forth heretofore.

If the solvent employed is of such characproduct be so low as to prevent obtaining a profit from the product thereof, then the entire tankage, after reduction, may be immediately subjected to a degreasing process as set forth and subjected to gasoline or naphtha as a solvent. extent the palatable quantities of the remainder but may not destroy its nutrition value. be employed in such instances when for some reason or other the price of feed is low and the price of grease would be relatively high or staple.

The process described in the aforementioned publication produces a product resulting therefrom suitable for feeding purposes and a. reject that, following the removal of the metallic portion, is suitable for a fertilizer base and this fertilizer base material is relatively dry and contains a considerable portion of grease. When a sufficient amount of the same has accumulated the same is placed in a tank or a receptacle of the character hereinafter described and subjected to an extraction process and to a drying, if necessary or de- In the drawings:

Fig. 1 is a diagrammatic elevational view of the extraction apparatus necessary to practice the process described, the extraction tank being shown in quarter section for greater clearance. Fig. 2 is a transverse section of the lower part of the extraction tank shown 1n Fig. 1 and the immediate connections thereto. Fig. 3 is an elevational view of the load sustaining perforated plate associated J with the extraction tank door shown in Figs.

This, of course, destroys to some This last mentioned procedure would- 1 and 2. Fig. 4 is a perspective View of a modified form of a load sustaining perforated late.

p In the drawings 10 indicates a vertical tank having a heating jacket 11 extcndingabout the bottom and partially up the side.' Wounted therein is an agitator 12 operable by motor 13 when drying the tankage. The tank has a supply neck 14 closed by cover 15 and an opening 16 in the side. Near the bottom a frame 17 surrounds the opening forming a chamber 18 having restricted communication with the tankby Way of perforated plate 19 having holes therein of dissimilar size (see Fig. 3). A door 20 completes the chamber and herein supports the plate. A pipe 21 communicates with the bottom portion of the tank by way of chamber 18. The jacket is supplied by lines 22 connected by line 23 and riser 24 to a source of steam pressure as boiler 124,-and controlled by valve 25. A line 26 also connected to the boiler is connected to valve 27. Lines 28 which discharge directly into the bottom of the tank for steam distillation are connected as at 29 and are controlled by valve 27.

A solvent supply tank 30 having filling member 31 and draining member 32 is connected to the line 21 by a reversible connection including a centrifugal pump 33 connected to four branches 34, each including a valve 35. \Vhen one diametrical pair of valves is opened and the other is closed the pump draws the solvent from tank 30 and pumps it into tank 10 if valve 36 is open. Closing the open valves and opening the closed valves causes the pump 33 to draw the solvent from tank 10 and discharge it to tank 30. The aforesaid washing may be repeated as often as desired or required.

A line 37 including valve 38 connects neck 14 with the boiler 124 and is used in pressing out the solvent. The neck 14 also includes a discharge line, 39 including valve 40 which connects to a'condenser not shown. When steam is admitted through pipes 22 it is discharged by line 39. Line 40 connects to the neck and includes valve 41 which is opened when all valves except 25 are closed. A Vacuum pump 42 operates to withdraw all vapors, particularly the moisture when pressing and distillation have been employed.

The present standard combination render ing tank is also satisfactory for use in the present process and consists of a vertical tank having an opemng or openings at the top and an opening or openings in or near the bottom. Said tank is jacketed at least 'part way throughout its length and on the bottom for heating the contents of the tank. Said tank also may beheat insulated. The tank may also contain an agitator, but in the simplified process use of the same is unnecessary. For complete drying the agitator shown herein may be utilized substantially as described in the copending application Serialtraction or extraction and drying, is placed vin a tank of suitable character as before indicated, and may be processed to form tankage of the character indicated in the before mentioned applications, or a separated constituent of said tankage may be placed in said tank for subsequent extraction, or ex-- traction and drying. Hereinafter in the specification and claims the terminology tankage is intended to include tankage formed by the process set forth in the pub-' lication before mentioned, or a separated constituent of said tankage as indicated, or the equivalents thereof.

Heat may be supplied to the tank jacket to heat the tankage prior to extraction provided such heating faciltates the extraction. In

the extraction of grease from the tankage bya solvent, such as gasoline, the activity of the solventis increased and the Viscosity of .the grease is decreased'by moderate heating.

If desired, the preliminary heating of the tankage and solvent, or either, may be omitted.

The tankage, whether heated or not, is

subjected to an extraction solvent. For

grease several solvents are commercially available. The cheapest and most readily accessible commercial solventis gasoline, or

a similar product such as naphtha and the like. This solvent is also one that is comgitliltlVGlY easy and relativelyfsafe to han The solvent is supplied to the tankage by being injected at or pumped into the bottom of the tank or substantially near the bottom of the tank, and it permeates uniformly through the tankage. Asit ipermeates upwardly throughsaid tankage, it carries with it the finer particles of the tankage washed from the larger particles near the bottom ofthe tank. "These finer particles when car'- ried upwardly tov the top of the tankage, form successive mats orlayers of gradually increasing finer tankage above the coarser particles. Thus, the continued injection of the solvent washes said larger particles free fromsmaller particles and removes all of the desired portion or extract from the larger particles, such as the grease when grease is to be extracted. The injection of solvent is continued until the same covers the tankage and it is determined that smaller particles of tankage have also been degreased.

When an agitator is included see Figs. 1 and 2, it is positioned so that the same is in alignment with the door or suitable piping used forthe injection of'the solvent. When this positioning is employed the solvent passes into the tank and along the passageway formed beneath or in the bottom of the arms of the agitatorand thus is conveyed finity for grease.

of this arrangement of superposed successively finer layers may be formed by the suc cessive introduction into the tank of the finer particles which will arrange themselves in the desired predetermined relationship prior to the injection of the solvent. This step of'the process whether secured by selective loading of the tank or automatically by the penetration of the uniformly distributed solvent, is hereinafter termed the filter formation in the specification and claims.

If desired heat may be applied to the jacket during this permeation period which 'increases the activity of the solvent in case of gasoline and the like and apparently its af- The temperature maintained, however, should be within reasonable limits and if the temperature is such that portion may be recovered through a suitable condenser.

After the solvent has been injected into i from the tankage to suitable agencies.

' a part of the solvent is distilled, this distilled 1 tub The character of the material will determine the injection pressure and solvent supply and the time'required for complete permeation. This invention, however, has reduced the permeation period far below the usual percolation periods on similar materials.

The removal of the solvent is accomplished in any suitable manner, or as follows: The solvent may first be permitted to drain from the tankage through a drain or suitable openings at or near the bottom of the tank. The solventinay also be pumped from the tank and tankage through thesupplyopenings. In this event the same pump utilized in forcing or injecting. the solvent through the tankage may be reversed and utilized for pumping off or removing said solvent. It

the solvent with the extracted constituentfrom the bottom thereof. If the solvent is supplied to the top of the tankage with or without pressure and the same is permitted to soak, then with the withdrawal of the solvent from the top of the tankage, it is impossible to extract the entire desired constituent from said tankage because the solvent does not completely percolate said tankage. By the foregoing it is not intended to convey the impression that the solvent will not pass through the tankage because the same may do so but the solvent will not completely permeate the charge of tankage. The solvent will find the easiest path through the charge of tankage and will follow the same, and thus as far as a practical extraction process is involved or concerned, the foregoing is'practically worthless.

Following permeation and withdrawal of the solvent from the tankage by this process described, the tankage has removed from it certain inhibiting properties which heretofore have prevented complete permeation by percolation. Generally the reduction in the inhibiting character of the tankage is proportional to the reduction or extraction of the desired constituent, and therefore, when substantially the desired degree of extraction has been obtained, the tankage is in a porous condition'sufficient to permit percolation. Therefore, there may be applied to the top of the tank pressure by way of superheated steam, steam, air or other suitable gases and percolation and passage of solvent and gas is permitted. This constitutes the pressing of the tankage and usually removes substantially all of the liquid solvent from the tankage through the bottom opening or openings.

By the foregoing it is intended to convey the idea that there remains in the tankage after the solvent has been removed by drainage, pumpage and pressing, but very little solvent comparedt'o present solvent reduction processes. The total loss of solvent, therefore, is reduced to an economic minimum. Merely by way of example, it may be stated that in-the degreasing of garbage the present process has operated with a loss of less than one-half gallon of gasoline to a ton of green garbage, whereas other degreasing operations have resulted in very much higher losses of solvent. Other degreasing operations aside from the loss of solvent, have resulted in high labor cost. The present process not only eliminates considerable labor but solvent recovery is'substantially complete.

The initial run or discharge of the extracting solvent in the case of grease-and gaso'- line may come out darkif the tankage includes considerable grease. When such is the case the tankage is subjected to a second cycle of operation, that. is, permeation with the solvent and the subsequent removal thereof and the aforesaid is repeated until it is commercially uneconomical to continue the same. Whenever, however, the color of the solvent indicates that a succeeding permeation is desirable, the pressing stages and subsequent steps are deferred until the solvent discharged from the tankage indicatesthat substantially all of the desired extractable material has been removed from the tankage. If desired, however, these subsequent steps ofpressing and those which follow may be employed after each cycle.

After the tankage has been sufliciently extracted and after pressing from the top of the tankage or if pressing is omitted immediately following the extraction, the gaseous medium is introduced into the tank at the bottom and substantially uniformly around the periphery of the tank by the several openings, which in the standard combination rendering tank arepositioned in spaced relation around i the periphery of the bottom of the tank.

Such a gaseous medium is preferably a dry gas, that is, dry steam and the same passes inwardly toward the center of the tankage and upwardly therethrough and completely permeates the same. Such passage is fac 1l1- tated by the beforementioned filter formation of the tankage. This application of steam simultaneously vaporizes any rema1ning liquid solvent and drives off the vaporized solvent in the tankage and in the tank through the upper opening or openings of the tank, This vaporized solvent may be' suitably collected in a suitable condenser. The foregoing, therefore, consists in drying the tankage by distillation.

The foregoing description includes pressing from the topv and distilling from the bottom. These two steps may be alternated and repeated whenever found necessary or desirable. Furthermore, the step of distillation from the bottom to the top may be omitted and the pressing continued from the top to the bottom with steam until sub'stan tially all of the liquid solvent has been pressed from the tankage or vaporized and the gaseous solvent distilled off. If desired the pressing. maybe omitted and all of the solvent in the tankage which has not been removed in the pumping or draining is vaporized and driven off in thedistillation from the bottom of said tankage. When steam is employed in the pressing, the same may be continued after allliquid solvent is removed end thereof. From the foregoing it will be evident that any desired numberof sequence of the foregoing steps may be employed upon the drainedtankage. In any event, whether the tankage following the pumping off or drainage of the solvent from the tankage, is subjected to pressing, steaming out or distillation or any or all of these or the same repeatedly, the resultant steps, tankage is substantially devoid of solvent and of any commerically removable content of the desired constituent. If desired the tankage may be mechanically agitated during the pressing, steaming out or distillation, or during any or all these steps.

While no special results will be obtained by having heat on the jacket during the pumping off operation, it may be found easier practice not'to out off the heat during this period. It

has been found advantageous, however, to supply heat to the jacket during the pressing and distillation periods.

the latter if sufliciently dry is removed from the tank through the usual door opening providednearthe bottom. This re moval will be performed manually when the tank is not provided with an agitator." When the tank is provided with an agitator, such as found in the standard combination rendering tank, the agitator may be operated to mechalriiically discharge the tankage from the tan If, however, the tankage following the substantially complete removal of the solvent -is not in the desired state of dryness, the same may be dried to the-said desired state by the continued application of heat to the jacket. Furthermore, to insure thorough drying and prevent caking along the sides of the tank, it may be highly advantageous to operate the agitator. during such drying, and furthermore, it may be found also desirable during this lastmentioned drying period to apply a vacuum to the tank, although generallyv direct discharge of the vapors during the drying period is suificient. v

Whenever the tankage is of such character that the tank apertured plate 19 is not satisfactory to retain the tankage within the tank, a suitable filter construction is substituted, and includes a box-like arrangement 119, see Fig. 4 secured to the door or. removablefrom the door opening if mounted adj acent to the door. Said box-like arrangement receives a filtering medium, such as excelsior, which preferably is boiled to soften the same.

'tors are not in motion,

Following the substantially complete removal of the extracting solvent from the tankag'e,

Other suitable mediums may, however, be substituted for the aforesaid filtering medium. The, perforated plate or box-like arrangement carried by the dooror removable from the door opening independently of the door, forms a straining surface ofsuflicient area to permit the straining of the solvent from the tankage with suificient rapidity, and

the filter will not permit the simultaneous withdrawal of any appreciable amount of finer tankage should any attcmpt to escape from the tank. This is particularly true if some of the finer material has not been carried upwardly to the top to form the matting previouslyreferred to. v 1

Furthermore, as previously suggested, operation of the. agitator while drying following distillation serves to insure uniformity of drying as well as rapidity of drying by pre-- venting caking of tankage upon the sides and bottom of the tank. If a single agitator such as commonly employed in the standard combination rendering tank, is not suflicient to secure the desired agitation ortankage movemerit, additional agitators may be associated therewith and these may have a common shaft. When agitators are provided, it is important that during such periodsas the agitathey shall be juxtapositioned with respect to openings.

The invention claimed is:

1. The process of garbage tankage extraction consisting of completely permeating a mass of substantially stationary tankage normally non percolatable in the mass and ineluding a solvent removable component by injecting solvent thereto from the bottom of the mass while stationary to eliminate packing thereof and to arrange said mass for subsequent solvent withdrawal, and thereafter removing the solvent from the bottom of the mass following said permeation.

2. The process of garbage tankage extraction consisting of completely permeating in a-container a mass of substantially stationary tankage normally non-pereolatable in the mass and including a solvent removable component by injecting a solvent thereto from the bottom of the mass while stationary toeliminate packing thereof, to arrange said mass for subsequent solvent withdrawal and to pass completely through'said mass, thereafter withdrawin the solvent from the en tire mass by withdrawing the same from the bottom of said mass, and thereafter drying the substantially solvent free tankage in the same container,

3.'A process ofextraction as defined by the mass for pressing the tankage and forcing the solvent from the bottom of said mass, and thereafter passing steam upwardly throu h the mass from the bottom of the mass for d1stilling the solvent in the mass and removing the same therefrom, the vaporized solvent passing upwardly through and from said mass.

5. A process of extraction as defined by claim 1, characterized by the addition of the application of steam pressure to the top of the mass for pressing the tankage and forcing the solvent from the bottom of said mass, thereafter passing steam upwardly through the mass from the bottom of the mass for distilling the solvent in the mass and removing the same therefrom, the vaporized solvent passing upwardly through and from said mass, and thereafter subjecting the mass in said container to a vacuum for removing the vapors therefrom.

6. A process of extraction as defined by claim 2, characterized by the addition of the application of steam pressure to the top of the mass for pressing the tankage and forcingthe solvent from the bottom of said mass.

A process of extraction as defined by claim 2, characterized by the addition of the application of steam pressure to the top of the mass for pressing the tankage and forcing the solvent from the bottom of'said mass,

and thereafter passing steam upwardly through the mass from the bottom of the mass for distilling the solvent in the mass and removing the same therefrom, the vaporized solvent passing upwardly through and from said mass.

8. A process of extraction as defined by claim 2, characterized by the addition ofthe application of steam pressure to the top of the mass for pressing the tankage and forcing the solvent from the bottom of said mass, thereafter passing steam upwardly through the mass from the bottom of the mass for distilling the solvent in the mass and removing the same therefrom, the vaporized solvent passing upwardly through and from said mass, and thereafter subjecting the mass in said container to a vacuum for removing the vapors therefrom.

In witness whereof, I have hereunto afiixed my signature.

ERVINQW. MCCULLOUGH. 

